2,6-Xylenol is used to prepare polyphenylene oxide which has utility as an engineering plastic.
Many catalysts are known for the preparation of 2,6-xylenol by the ortho-alkylation of phenol. For example, U.S. Pat. Nos. 3,972,836 and 4,041,085 teach the use of magnesium oxide. German publication No. 2,704,440 teaches the use of calcium oxide. German publication No. 2,716,035 teaches the use of copper chromite alone or in combination with MnO, ZnO, Al.sub.2 O.sub.3, or MnO.sub.2. U.S. Pat. No. 4,024,195 teaches the use of a combination of Fe.sub.2 O.sub.3 /SiO.sub.2 /Cr.sub.2 O.sub.3 /K.sub.2 O. U.S. Pat. No. 3,790,641 teaches the use of the following oxide components: Mg-Ce-Sn-V; Ce-Sc-Sn; La-Y-Sn.
The MgO based catalysts have the disadvantage of requiring a high reaction temperature (e.g. 475.degree.-525.degree. C.): additionally, they have a lower selectivity as compared to the catalyst used in the present invention. Iron oxide based catalysts alone have very low activity. Use of vanadium oxide in combination with iron oxide improves the activity but results in high methanol decomposition. The Fe.sub.2 O.sub.3 /SiO.sub.2 /Cr.sub.2 O.sub.3 /K.sub.2 O catalyst works well but results in the formation of an undesirable amount of BTX (benzene, toluene, xylenes). The catalyst of my invention, as compared to the aforementioned catalyst, has the advantage of having a higher selectivity in preparation of 2,6-xylenol and the production of less BTX.